ENVIRONMENTAL PROTECTION TYPE DENSE FLINT GLASS WITH HIGH REFRACTIVE INDEX AND HIGH DISPERSION, AND METHOD AND DEVICE FOR PREPARING THE SAME

摘要

An environmental protection type dense flint glass with high refractive index and high dispersion is provided, the glass comprises, in wt%, SiO<SUB>2</SUB> 20-44, TiO<SUB>2</SUB> 22-34, Nb<SUB>2</SUB>O<SUB>5</SUB> 5-22, Na<SUB>2</SUB>O 7-18, BaO 9-17, K<SUB>2</SUB>O 0-9, CaO 0-3, ZrO<SUB>2</SUB> 0-3, SrO 0-0.5 and Sb<SUB>2</SUB>O<SUB>3</SUB> 0-0.5. A method for preparing the above glass is also provided, the method comprises the following the steps: 1) mixing raw materials sufficiently to allow them to be uniformly distributed; 2) melting the raw materials to an glass melt in a tank furnace at 1150-1300 ºC to ensure uniform refractive index; 3) molding the glass melt into glass strips after refining and homogenizing the glass melt having qualified refractive index; and 4) annealing the glass strips in the annealing oven. The device for producing the above glass comprises a tank furnace and an annealing oven, wherein the molten pool of the tank furnace is connected with automatically combustion-controlling system. The glass is free of PbO, As<SUB>2</SUB>O<SUB>3</SUB> and GdO which pollute environment, and is produced in a mode of melting the raw material at a time, thereby decreasing the number of melting raw materials at high temperature and enhancing the optical transmittance.